HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Oostrom, M. Articles by Wietsma, T. W. Search for Related Content PubMed Articles by Oostrom, M. Articles by Wietsma, T. W. GeoRef GeoRef Citation Agricola Articles by Oostrom, M. Articles by Wietsma, T. W. Related Collections Volatile Organic Compounds Experiment Design

ORIGINAL RESEARCH

Removal of Carbon Tetrachloride from a Layered Porous Medium by Means of Soil Vapor Extraction Enhanced by Desiccation and Water Table Reduction

^a Environmental Technology Division, Pacific Northwest National Lab., P.O. Box 999, MS K9-33, Richland, WA 99354
^b Dep. of Agronomy and Soils, Auburn Univ., Auburn, AL 36849-5412
^c Environmental Molecular Sciences Lab., Pacific Northwest National Lab., P.O. Box 999, MS K8-96, Richland, WA 99354
^* Corresponding author (mart.oostrom{at}pnl.gov)

Received 3 December 2004.

A two-dimensional flow cell experiment was conducted to study the removal of the carbon tetrachloride component of a DNAPL mixture from a layered porous medium through soil vapor extraction (SVE) with moist and dry air. A dual-energy radiation system was used at various times to non-intrusively determine fluid saturations. The mixture, which contained the volatile organic carbon tetrachloride, mimics the DNAPL disposed at the Hanford Site in Washington State. The flow cell, which is 100 cm long, 75 cm high and 5.5 cm wide, was packed with two sloped coarse sand and two sloped silt layers in an otherwise uniform matrix of medium-grained sand. A V-shaped fine sand layer was placed at the bottom of the flow cell to prevent DNAPL from exiting the flow cell. The water table was located 2 cm from the bottom, creating variably saturated conditions. A 500-mL spill was introduced at the top of the flow cell from a small source area. It was observed that the DNAPL largely by-passed the silt layers but easily moved into the coarse sand layers. Residual DNAPL was formed in the medium-grained sand matrix. The DNAPL caused a distinct reduction of the capillary fringe. Most of the DNAPL ended up in a pool on top of the V-shaped fine sand. Through four treatments with moist air soil vapor extraction, most residual carbon tetrachloride was removed from the medium-grained matrix and the coarse sand layers. However, soil vapor extraction with moist air was not able to remove the carbon tetrachloride from the silt layers and the pool. Through a water table reduction and subsequent soil vapor extraction with dry air, the carbon tetrachloride in the silt layers and the pool was effectively removed. Based on measurements and carbon tetrachloride vapor concentration data, it was estimated that after the final remediation treatment, almost 90% of the total mass was removed.

Abbreviations: DBBP, dibutyl butyl phosphonate • DNAPL, dense non-aqueous phase liquid • DSVE, dry soil vapor extraction • PCE, perchloroethylene • SVE, soil vapor extraction • TBP, tributyl phosphate • TCE, trichloroethylene • VOC, volatile organic compound • WSVE, wet soil vapor extraction

This article has been cited by other articles:

				M. Oostrom, J. H. Dane, and T. W. Wietsma A Review of Multidimensional, Multifluid, Intermediate-Scale Experiments: Flow Behavior, Saturation Imaging, and Tracer Detection and Quantification Vadose Zone J., August 23, 2007; 6(3): 610 - 637. [Abstract] [Full Text] [PDF]

				M. Oostrom, J. H. Dane, and T. W. Wietsma A Review of Multidimensional, Multifluid Intermediate-Scale Experiments: Nonaqueous Phase Liquid Dissolution and Enhanced Remediation Vadose Zone J., May 26, 2006; 5(2): 570 - 598. [Abstract] [Full Text] [PDF]